I'm writing a story set in a fictional world (the exact setting is a city centered on a desert oasis and in the nearby canyons) in which there are two species of humanoids (who mostly pretend that the other doesn't exist). Humans (as we known them today, with the addition of magic -- because magic makes everything better :D) are the majority in the city, while the other species lives in the outlands.
The second species is an as yet unnamed species that is basically what humans might look like if we were descended from marsupials, or rather, what we might look like if we were descended from marsupials that never diverged from monotremes -- more on that in a bit. (I figure basically any set of traits is possible with evolution, given enough time and the right selective pressures, but if I mention anything that raises a red flag for anyone, please do let me know.) The main character is a member of this species; he also has a small child.
Questions on vocal cords:
I'd like the fictional species to be able to purr/growl/etc. as well as having a spoken language. I've googled the mechanics on how cats purr (this site and this one were pretty useful) as well as the mechanics of human vocal cords. Bizarrely, I was not able to find much on the latter (search terms "vocal chords," "how vocal chords work," and "how do vocal chords work?" eta: I'ma have to try spelling it right...) though there's a decent summary here. I have not encountered any information that suggests that purring/growling is incompatible with human speech; is this a valid conclusion?
If so, would an individual be able to purr/growl and speak at the same time? (The specific scene I'm wondering about has him comforting his son by purring. Would it be valid for him to speak at the same time, ie. "Shh, it's okay" or something to that effect?) I've tried to figure it out based on the information I gleaned from the aforementioned links, but I really don't know enough about the subject to draw the appropriate conclusions.
I knew from the beginning that the species would have pouches for raising young (like marsupials). Plot made it necessary for my (male) character to have a pouch (though no male marsupials in our world have one) because his wife is killed when their son is still developing. Also, in female marsupials, the nipples are located inside the pouch, so any female marsupial humanoid would have no breasts -- which would certainly be an interesting idea, but was not what I had in mind for this particular story. That being said, I've gotten a little creative with the details of reproduction/child development, drawing from sources about marsupials (information gotten here and here), seahorses (from a bunch of sources, but this one was a pretty good summary), and even monotremes (though they don't have pouches and that line of research didn't really pan out). I've gotten what I feel is a feasible process, but I still have some kinks that I can't work out:
Note: Steps 2-4 are based on seahorses; step 5 is based on marsupials; step 6 I made up).
1) Fertilization (the same way people do it).
2) Egg develops in female's body.
3) Female lays egg, male deposits it in his pouch.
4) The shell is absorbed by the male's body. Question: Given this information, would it make more sense for the shell to be hard (like a bird's) or soft (like some reptiles')?
5) The embryo develops in a nutrient-filled sac in the pouch. Question: I couldn't find any information on how much a marsupial's pouch regulates the environment of the developing offspring. Is it just a safe place for the fetus to develop, or does some regulation occur? They do not share a blood supply (this is also true of my fictional species) so I know there would be a lot less than in eutherians (where nutrients, oxygen, etc. is transferred into the placenta and waste is transferred out) but I figured there had to be something, or there wouldn't be a need for a pouch.
6) When the offspring has finished developing (by which I mean s/he reaches infancy) they break through the sac (or perhaps it's absorbed...?) and begin nursing with the mother, though s/he still spends most of his/her time in the father's pouch until a few years of age.
I'm also looking for the specific advantage/disadvantages of this sort of system. The sites I listed before gave me some good ideas, but I still mostly have advantages (e.g. by necessity, parents share child care, which fosters strong "maternal instinct" (so to speak) between father-child as well as mother-child) but I am having trouble coming up with disadvantages. I do not want a super species, just one that is different. So far I have the obvious (the offspring are born very undeveloped and can easily be affected by the environment). Some of the sites I looked at indicated that marsupials have a much lower reproduction rate, so I figure I can use that, but I can't find a good reason for why this is the case (googling "marsupials +'low reproductive rate'" gave me some really vague reasons but nothing solid), and I'd like to know before I incorporate it in in a story. Can anyone else think of any disadvantages to this kind of system (whether it's very vague or so obvious that I missed it)?
I've been rock climbing since about the time I could walk (it's what you get when your dad is a mountaineer), so I'm not asking for technical details because I either know them already or know where to look. However, the species' native habitat is a desert canyon/mountain setting, and they spend most of their lives either in caves or on vertical surfaces. As well as good climbing skills (obviously) I was thinking that it would be useful if they had some mechanism that helped them hold onto the rock wall. I was thinking something like a gecko, but that system won't work for something the size of a human, even if I lighten their bone structure. (In case you're wondering, geckos can walk up walls because they have tiny hairs on the bottoms of their feet. This helps them stick because of Van der Waal's forces, which are most definitely too weak to hold up something heavier than a small lizard. Also, I'd like to avoid the train of thought that hairy palms is likely to cause. :P) If necessary, I can give them some sort of magic that helps, but ideally I'd like a physical structure (a point of contention in the story is that humans can use magic and this species can't). I have not done any googling for this, mostly because I haven't the faintest idea where to start. Any ideas (for either a system or some search terms)?
Also related to their environment, and something else that I don't know how to start researching: Children who are too big to ride in their father's pouches ride on their parents' backs (like opossums). I was thinking they would probably hold around the neck, but I'm concerned that this would, well, limit the parents' ability to breathe! What sort of adaptations might be needed to prevent this? I considered some sort of bone structure, but I was concerned that might be self-defeating (that it might inhibit the windpipe's ability to expand). Help?
And I haven't had a chance to research this yet, but can anyone point me to good sites regarding Japanese bonsai/minature trees? (One of the human characters is a green mage with an interest in them.)
'Kay, I think that's it. (Long post is long.)
Edited: to fix a spelling and word choice mistake.